Terminally unsaturated vinyl ester resins prepared by reacting a polyepoxide with a dicarboxylic acid half ester of a hydroxyalkyl acrylate or methacrylate are disclosed in U.S. Pat. No. 3,367,992. While these resins have many useful properties, their use in applications which require flexibility in the thermoset resin is limited. Those applications where flexibility is important include coatings, binders and adhesives.